NO HEAT AGAIN !

I'm back. I had heat (see former post - NO HEAT) for about 3/4 days after reversing the hose that goes to the heater core input (output went into
a container)...then it was back to the way it was before, blowing air that wouldn't even get warm. Today...I pulled the hoses off the heater core and hooked the garden hose up to it and flushed it out good. Nothing strange came out...just Dexcool...then water. After starting the truck, with the hoses still off and the rad cap off, I got about 1/2 gallon of Dexcool out of the hose that runs from the thermostat side. The truck was cold. I could see getting *some* Dexcool from the hose, but 1/2 gallon? Seems a lot to me when the thermostat should be closed. It sounds to me like I may have a stuck thermostat (yet the needle on gauge is almost normal, only one peg down than what it normally is). If so, why does it start working when I flush the heater core? Or...could I have an air bubble in the heater core? What about the wrong amount of Dexcool...can I be over-cooling it? Do you mix this stuff with water like the regular anti-freeze? (Hey, I'm learning!).
Ideas?
B|ondie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 23 Nov 2004 02:55:07 GMT, in alt.autos.4x4.chevy-trucks you wrote:

Put it back together and fill it up. Start it and bring it up to temp. Chech both heater hoses from core. If only 1 is hot then your still blocked up. If both are hot then maybe your heater control isn't working right.........
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Brian, I hooked it all back up on Monday after I flushed it. I have plenty of heat now. The problem is, is that after a few days, I have no heat at all again. I can only wait and see if it does it again.
And yes, the output of the heater core was cold after the truck warmed up before I did this the first time...which was what told me to flush the heater core. After a few days...it was cold again.
The really strange thing was, that I got 1/2 gallon of Dexcool out of the hose when I started the truck after I flushed the heater core the second time. Unless I'm wrong...the thermostat is supposed to be closed when the engine is cold. If it was a faulty heater control, why would flushing the heater core make it heat again?
My question are ...could I have an air bubble, or can it be overcooled...and why so much Dexcool when starting a cold engine?
Thanks, B|ondie
Brian wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Blondie,
Did you grab a Stant venting rad cap like I suggested and burp the system after fiddling with it? If not, trapped air may be causing your recent set of problems. The heater core in your truck is at the highest point of the cooling circuit so guess where the air ends up?
Anywho, yes an engine can be overcooled and perhaps your t-stat is stuck open. It is prudent to replace the t-stat after every flush/drain as safe measure. Is the truck taking longer to heat up than it used to? Is the upper rad hose getting warm slowly or does it just get really hot really fast like it should when the stat pops open?
Regarding the Dex when you started it up, it was probably just what was in the line and that part of the circuit; I wouldn't worry about it.
Doc

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.